Comparison of metabolome profiles in zebrafish (Danio rerio) intestine induced by polystyrene microplastics with different sizes.

Abstract

Microplastics (MPs) are widespread in aquatic environments. They could induce intestinal toxicity in the fish. However, research on the metabolic toxicity of polystyrene microplastics (PS-MPs) with different particle sizes to the zebrafish intestine is still limited. Here, metabolomics using ultra-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was applied to characterize the metabolic disorders in zebrafish intestine after exposure to 500μg/L PS-MPs with different sizes (100nm, 5μm, and 200μm) for 21days. Results showed that the 100nm PS-MPs group increased glutathione content. A total of 35, 165, and 87 metabolites were significantly altered in zebrafish intestines of 100nm, 5μm, and 200μm groups under positive ion mode, respectively. In comparison, 31, 115, and 45 metabolites were changed in the 100nm, 5μm, and 200μm groups under negative ion mode, respectively. Metabolic pathway analysis indicated that carbohydrate metabolism, amino acid metabolism, and nucleotide metabolism were changed in all three groups. The greatest changes were found in the 5μm group. Moreover, treatment with micro-sized PS-MP groups specifically changed lipid metabolism, which might be related to pathogenic bacteria (Streptococcus and Moraxella). In the 100nm PS-MP group, S-adenosyl-L-methionine (SAM) was found to be markedly related to the intestinal microbiota. SAM level was significantly increased, which might account for the elevated glutathione content. To sum up, the mechanisms of nano-sized MPs (oxidative stress) and micro-sized MPs (lipid metabolism disorder) were distinct. This study provides novel insight into the toxicity mechanism of MPs in the zebrafish intestine.